Glass and method of manufacturing the same

ABSTRACT

A method of manufacturing a glass includes forming a first etch protection layer on a first surface of a glass substrate, and forming a second etch protection layer on a second surface of the glass substrate; removing a part of the first protection layer and a part of the second protection layer by applying a laser pulse penetrating the glass substrate from above the first surface of the glass substrate; forming a cut part in the glass substrate by etching the glass substrate using an etching solution; and removing the first etch protection layer and the second etch protection layer. The second surface is opposite to the first surface.

This application is a divisional of U.S. patent application Ser. No.17/529,736, filed on Nov. 18, 2021, which claims priority to KoreanPatent Application No. 10-2020-0157805, filed on Nov. 23, 2020, and allthe benefits accruing therefrom under 35 U.S.C. § 119, the content ofwhich in its entirety is herein incorporated by reference.

BACKGROUND Field

Embodiments described herein relate to a glass and a method ofmanufacturing a glass.

Background

A display device is a device emitting light to display an image. In thedisplay device, a display part displaying the image may be protected bya glass. The glass may be formed by cutting a glass substrate tocorrespond to a shape of the display part.

SUMMARY

When the glass substrate is cut by dry etching (for example, lasercutting method), a cut part of the glass substrate may be damaged.Accordingly, a mechanical strength of the cut part may be lowered. And,an additional process to chamfer an edge of the cut part may bedesirable.

Some embodiments provide a method of manufacturing a glass preventing acut part of the glass from damaging and performing cutting of the glassand chamfering of an edge of the cut part in a single process.

Some embodiments provide a glass that an edge of a cut part ischamfered.

According to some embodiments of present invention concept, a method ofmanufacturing a glass may include: forming a first etch protection layeron a first surface of a glass substrate; forming a second etchprotection layer on a second surface of the glass substrate; removing apart of the first protection layer and a part of the second protectionlayer by applying a laser pulse penetrating the glass substrate fromabove the first substrate of the glass substrate; forming a cut part inthe glass substrate by etching the glass substrate using an etchingsolution; and removing the first etch protection layer and the secondetch protection layer. The second surface is opposite to the firstsurface.

According to some embodiments, the part of the first etch protectionlayer may be removed by a first width by the laser pulse, and the partof the second etch protection layer may be removed by a second width bythe laser pulse.

According to some embodiments, the method may further include adjustinga size of the first width and a size of the second width.

According to some embodiments, the size of the first width and the sizeof the second width may be adjusted based on an intensity of the laserpulse.

According to some embodiments, the size of the first width and the sizeof the second width may be adjusted based on a material of the firstetch protection layer, a material of the second etch protection layer,and a wavelength of the laser pulse.

According to some embodiments, the wavelength of the laser pulse may beabout 343 nanometers (nm) or more and about 355 nm or less.

According to some embodiments, the size of the first width may begreater than the size of the second width.

According to some embodiments, the size of the first width may besubstantially the same as the size of the second width.

According to some embodiments, a shape of the cut part in across-section view may be adjusted based on the size of the first widthand the size of the second width.

According to some embodiments, a transmittance of the glass substratewith respect to the laser pulse may be about 50 percentages (%) or more.

According to some embodiments, the glass substrate may further include amodified part modified by the laser pulse.

According to some embodiments, an etch rate of the modified part may begreater than an etch rate of a non-modified part of the glass substrate.

According to some embodiments, a shape of the cut part may be adjustedbased on a width of the modified part.

According to some embodiments, the method may further include generatingthe laser pulse; and irradiating the glass substrate with the laserpulse through a laser scanning unit.

According to some embodiments, the laser scanning unit may include anf-theta lens.

According to some embodiments, forming the cut part in the glasssubstrate may include spraying the etching solution on the glasssubstrate.

According to some embodiments, forming the cut part in the glasssubstrate may further include dipping the glass substrate in the etchingsolution.

According to some embodiments, the etching solution may include at leastone of hydrofluoric acid, hydrochloric acid, and ammonium fluoride.

According to some embodiments of the present inventive concept, a glassincludes an upper surface, a lower surface opposite to the uppersurface, and a side surface connecting the upper surface and the lowersurface. The side surface includes a cut part. The cut part includes afirst chamfered part and a second chamfered part. The first chamferedpart is concave, has a first curvature radius, and is adjacent to theupper surface. The second chamfered part is concave, has a secondcurvature radius, and is adjacent to the lower surface. The secondcurvature radius is less than the first curvature radius.

According to some embodiments, the cut part may further include a flatpart connecting the first chamfered part and the second chamfered part.

In the present inventive concept, after forming the protection layers onopposite major surfaces of the glass substrate, the etch protectionlayers may be removed with a laser pulse. Accordingly, the number ofprocesses required for glass manufacturing may be effectively reduced.

In the present inventive concept, the glass substrate may be etched andcut with an etching solution, and at the same time, the edge of the cutpart may be chamfered. Accordingly, damage to the cut part may beeffectively prevented, and an additional process for chamfering may notbe required.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate exemplary illustrativeembodiments of the invention, and together with the description serve toexplain the inventive concepts.

FIG. 1 is a flow chart showing a glass manufacturing method according toan embodiment.

FIGS. 2, 3, 4, 5, and 6 are perspective view showing a glassmanufacturing method according to an embodiment.

FIG. 7 is a cross-sectional view taken along line of FIG. 4 .

FIG. 8 is a graph for explaining a method of adjusting a size of a firstwidth and a size of a second width of FIG. 7 .

FIG. 9 is a graph for explaining a method of adjusting a size of a firstwidth and a size of second width of FIG. 7 .

FIGS. 10, 11, and 12 are cross-sectional views taken along line II-II′of FIG. 5 .

FIGS. 13 and 14 are cross-sectional views taken along line II-II′ ofFIG. 5 .

FIG. 15 is a diagram for explaining a laser pulse according to anembodiment.

FIG. 16 is a perspective view showing a glass substrate according to anembodiment.

FIG. 17 is a cross-sectional view of the glass substrate of FIG. 16taken along line in a first direction.

FIG. 18 is a perspective view showing a glass substrate according toanother embodiment.

FIG. 19 is a cross-sectional view of the glass substrate of FIG. 18taken along line in the first direction.

DETAILED DESCRIPTION

It will be understood that when an element is referred to as being “on”another element, it can be directly on the other element or interveningelements may be present therebetween. In contrast, when an element isreferred to as being “directly on” another element, there are nointervening elements present.

It will be understood that, although the terms “first,” “second,”“third” etc. may be used herein to describe various elements,components, regions, layers and/or sections, these elements, components,regions, layers and/or sections should not be limited by these terms.These terms are only used to distinguish one element, component, region,layer or section from another element, component, region, layer orsection. Thus, “a first element,” “component,” “region,” “layer” or“section” discussed below could be termed a second element, component,region, layer or section without departing from the teachings herein.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting. As used herein, thesingular forms “a,” “an,” and “the” are intended to include the pluralforms, including “at least one,” unless the content clearly indicatesotherwise. “At least one” is not to be construed as limiting “a” or“an.” “Or” means “and/or.” As used herein, the term “and/or” includesany and all combinations of one or more of the associated listed items.It will be further understood that the terms “comprises” and/or“comprising,” or “includes” and/or “including” when used in thisspecification, specify the presence of stated features, regions,integers, steps, operations, elements, and/or components, but do notpreclude the presence or addition of one or more other features,regions, integers, steps, operations, elements, components, and/orgroups thereof.

Furthermore, relative terms, such as “lower” or “bottom” and “upper” or“top,” may be used herein to describe one element's relationship toanother element as illustrated in the Figures. It will be understoodthat relative terms are intended to encompass different orientations ofthe device in addition to the orientation depicted in the Figures. Forexample, if the device in one of the figures is turned over, elementsdescribed as being on the “lower” side of other elements would then beoriented on “upper” sides of the other elements. The exemplary term“lower,” can therefore, encompasses both an orientation of “lower” and“upper,” depending on the particular orientation of the figure.Similarly, if the device in one of the figures is turned over, elementsdescribed as “below” or “beneath” other elements would then be oriented“above” the other elements. The exemplary terms “below” or “beneath”can, therefore, encompass both an orientation of above and below.

“About” or “approximately” as used herein is inclusive of the statedvalue and means within an acceptable range of deviation for theparticular value as determined by one of ordinary skill in the art,considering the measurement in question and the error associated withmeasurement of the particular quantity (i.e., the limitations of themeasurement system). For example, “about” can mean within one or morestandard deviations, or within ±30%, 20%, 10% or 5% of the stated value.

Hereinafter, embodiments of the present invention will be explained indetail with reference to the accompanying drawings.

FIG. 1 is a flow chart showing a glass manufacturing method according toan embodiment.

Referring to FIG. 1 , a glass manufacturing method may include: formingetch protection layers on opposite major surfaces of a glass substrate(S1); removing a part of the protection layers by applying a laser pulse(S2); cutting the glass substrate by etching with an etching solution(S3); and removing the etch protection layers (S4).

FIG. 2 , FIG. 3 , FIG. 4 , FIG. 5 , and FIG. 6 are perspective viewshowing a glass manufacturing method according to an embodiment.

Referring to FIG. 2 , a glass substrate 10 may be prepared. The glasssubstrate 10 may include a first surface 10F and a second surface 10B.The second surface 10B may be opposite to the first surface 10F. In FIG.2 , the glass substrate 10 having a rectangular shape is illustrated,but a shape of the glass substrate 10 according to the invention is notlimited to the rectangular shape. In another embodiment, for examples,the shape of the glass substrate 10 may be a round shape. The glasssubstrate 10 may include soda-lime, alumo-boro-silicate, earth alkalialumo-silicate, or earth alkali alumo-boro-silicate.

Referring to FIG. 1 and FIG. 3 , etch of etch protection layers 21 and22 may be formed on each of the opposite major surfaces 10F and 10B ofthe glass substrate 10 (S1). Specifically, a first etch protection layer21 may be formed on the first surface 10F. A second etch protectionlayer 22 may be formed on the second surface 10B. The etch protectionlayers 21 and 22 may have a relatively low etch rate with respect to anetching solution. For example, with respect to the etching solution, theetch rate of the etch protection layers 21 and 22 may be lower than anetch rate of the glass substrate 10. The etch protection layers 21 and22 may prevent the glass substrate 10 from contacting with the etchingsolution. The etch protection layer 21 and 22 may protect the glasssubstrate 10 from being etched.

Referring to FIG. 1 and FIG. 4 , a part of the etch protection layers 21and 22 may be removed by laser pulse 30 (S2). Specifically, the laserpulse 30 may enter the glass substrate from above the first surface 10Fof the glass substrate 10. Accordingly, the laser pulse 30 may removethe first etch protection layer 21 and then penetrate the glasssubstrate 10 to remove the second etch protection layer 22. A part ofthe first etch protection layer 21 and a part of the second etchprotection layer 22 may be removed and then the first surface 10F andthe second surface 10B of the glass substrate 10 may be exposed. Thefirst etch protection layer 21 and the second etch protection layer 22may include the same material.

The laser pulse 30 may have different intensity depending on location. Adistribution of the intensity of the laser pulse 30 may be a Gaussiandistribution. The intensity of the laser pulse 30 may be greatest at acenter of the laser pulse 30. In an embodiment, the laser pulse 30 mayinclude excimer laser pulse, YAG laser pulse, glass laser pulse, YV04laser pulse, Ar laser pulse, ruby laser pulse, etc.

Each of the etch protection layers 21 and 22 may have an ablationthreshold. When the laser pulse 30 having intensity equal to or greaterthan the ablation threshold is applied to each of the etch protectionlayers 21 and 22, the etch protection layers 21 and 22 may be removed.

In an embodiment, the etch protection layers 21 and 22 formed on theopposite major surfaces 10F, 10B of the glass substrate 10 may beremoved at the same time by the laser pulse 30. Accordingly, the numberof processes required for the glass manufacturing method may be reduced,and mass productivity may be increased.

The laser pulse 30 may penetrate the glass substrate 10. For example,some of the laser pulse 30 may be absorbed by the glass substrate 10 andsome of the laser pulse 30 may penetrate the glass substrate 10. Whenthe laser pulse 30 is perfectly absorbed by the glass substrate 10, thesecond etch protection layer 22 may not be etched. In an embodiment, atransmittance of the glass substrate 10 with respect to the laser pulse30 may be about 50 percentages (%) or more.

The laser pulse 30 may be absorbed by the glass substrate 10, and thelaser pulse 30 may modify the glass substrate 10. Accordingly, a part ofthe glass substrate 10 in which the laser pulse 30 is absorbed maybecome a modified part 11. Specifically, the laser pulse 30 may beinductively absorbed by the glass substrate 10, and form the modifiedpart 11 on the glass substrate 10. An etch rate of the modified part 11may be greater than an etch rate of a part of the glass substrate 10that is not modified by the laser pulse 30.

Referring to FIG. 1 and FIG. 5 , a part of the glass substrate 10 may beremoved by etching with an etching solution to form a cut part 12 (S3).Specifically, the glass substrate 10 may be etched by the etchingsolution. A part of the first surface 10F and the second surface 10B ofthe glass substrate 10 that is not protected by the etch protectionlayers 21 and 22 may be etched by contacting with the etching solution.An etch rate of the modified part 11 with respect to the etchingsolution may be relatively high, and thus, may be etched relativelyquickly. A part of the glass substrate 10 that is etched and removed bythe etching solution may form the cut part 12.

The etching solution may be sprayed on the opposite major surfaces 10Fand 10B of the glass substrate 10, or the glass substrate 10 may beimmersed in the etching solution. In an embodiment, the etching solutionmay include at least one of the hydrofluoric acid, hydrochloric acid,and ammonium fluoride.

The etch rate of each of the etch protection layers 21 and 22 withrespect to the etching solution may be relatively low. That is, the etchrate of the etch protection layers 21 and 22 may be lower than an etchrate of the glass substrate 10 with respect to the etching solution. Inan embodiment, the etch protection layers 21 and 22 may have acidresistance.

In the present inventive concept, since the glass substrate 10 is cut bywet etching method using the etching solution, damage to the cut part 12of the glass substrate 10 may be effectively prevented. In addition,since the glass substrate 10 and the etching solution are in contactwith each other through the removed part of the etch protection layers21 and 22, the cut part 12 may have a shape in which the edges arechamfered.

Referring to FIG. 1 and FIG. 6 , the etch protection layers 21 and 22may be removed (S4). So, the glass substrate 10 having the cut part 12may be formed.

FIG. 7 is a cross-sectional view taken along line of FIG. 4 .

Referring to FIG. 4 and FIG. 7 , A part of the first etch protectionlayer 21 may be removed by the laser pulse 30, and a width of a removedpart of the first etch protection layer 21 on a major surface plane ofthe first etch protection layer 21 may be a first width W21. The majorsurface plane is defined by the first direction DR1 and a seconddirection DR2. (See FIG. 16 ). The second etch protection layer 22 maybe removed by the laser pulse 30, and a width of a removed part of thesecond etch protection layer 21 on a major surface plane of the secondetch protection layer 22 may be a second width W22. A width of themodified part 11 modified by the laser pulse 30 on a major surface planeof the glass substrate 10 may be a third width W11.

The first width W21 and the second width W22 may be adjusted.Specifically, a size of the first width W21 and a size of the secondwidth W22 may be adjusted by adjusting an intensity of the laser pulse30, a wavelength of the laser pulse 30, a material of the first etchprotection layer 21, and a material of the second etch protection layer22.

In an embodiment, the size of the first width W21 may be larger than thesize of the second width W22, or the size of the first width W21 may besubstantially same as the size of the second width W22.

FIG. 8 is a graph for explaining a method of adjusting a size of a firstwidth and a size of a second width of FIG. 7 .

Referring to FIG. 7 and FIG. 8 , a y-axis of the graph of FIG. 8 meansrelative intensity of the laser pulse 30, and an x-axis of the graph ofFIG. 8 means location (micrometers (μm)). A distribution of an intensityof the laser pulse 30 may be a Gaussian distribution. The distributionof the intensity of laser pulse 30 may be a first distribution ofintensity I1, a second distribution of intensity I2, or a thirddistribution of intensity I3. The graph of FIG. 8 sets maximum intensityof the first distribution of intensity I1 to 1, and the relativeintensity distribution accordingly is shown. That is, maximum intensityof the second distribution of intensity I2 is 0.5, and maximum intensityof the third distribution of intensity I3 is 0.25. The etch protectionlayers 21 and 22 may have an ablation threshold. The etch protectionlayers 21 and 22 may not be etched by the laser pulse 30 havingintensity that is lower than the ablation threshold. The etch protectionlayers 21 and 22 may be etched by the laser pulse 30 having intensitythat is equal to or greater than the ablation threshold.

When the distribution of the intensity of the laser pulse 30 is thefirst distribution of intensity I1, a width by which the first etchprotection layer 21 is removed and a width by which the second etchprotection layer 22 is removed may each be a third width W3. When thedistribution of the intensity of the laser pulse 30 is the seconddistribution of intensity I2, a width by which the first etch protectionlayer 21 is removed and a width by which the second etch protectionlayer 22 is removed may each be a second width W2. When the distributionof the intensity of the laser pulse 30 is the third distribution ofintensity I3, a width by which the first etch protection layer 21 isremoved and a width by which the second etch protection layer 22 isremoved may each be a first width W1.

As described above, as the intensity of the laser pulse 30 is adjusted,the sizes of the first width W21 and the second width W22 may beadjusted.

FIG. 9 is a graph for explaining a method of adjusting a size of a firstwidth and a size of second width of FIG. 7 .

Referring to FIG. 7 and FIG. 9 , the graph of FIG. 9 shows transmittanceof the laser pulse penetrating each of the materials when the laserpulse 30 of different wavelengths are irradiated to different materials.

The etch protection layers 21 and 22 may include polystyrene,polycarbonate, Poly(methyl methacrylate) (“PMMA”), or ultravioletacrylic, and each of the materials may have a different transmittancefor the laser pulse 30 of a specific wavelength. When a transmittance ofeach of the first etch protection layer 21 and the second etchprotection layer 22 is relatively high (for example, the transmittanceis about 80%), an amount of the laser pulse 30 that is absorbed by theetch protection layers 21 and 22 may be relatively lowered. Accordingly,a process time for removing the etch protection layers 21 and 22 may berelatively long, and the size of the first width W21 and the size of thesecond width W22 may be relatively reduced.

In an embodiment, in order that the etch protection layers 21 and 22 cantransmit the laser pulse 30 relatively less, a material of the firstetch protection layer 21, a material of the first etch protection layer22, and a wavelength of the laser pulse 30 may be adjusted.

In an embodiment, the wavelength of the laser pulse 30 may be about 343nanometers (nm) or more and about 355 nm or less. When the wavelength ofthe laser pulse 30 may be about 343 nm or more and about 355 nm or less,the transmittance of the laser pulse 30 may be relatively low for mostmaterials (for example, polystyrene, polycarbonate, and PMMA). So, bysetting the wavelength of the laser pulse 30 to about 343 nm or more andabout 355 nm or less, a rate of absorption of the laser pulse 30 formost materials may be relatively high.

FIG. 10 , FIG. 11 , and FIG. 12 are cross-sectional views taken alongline II-II′ of FIG. 5 .

Referring to FIG. 10 , FIG. 11 , and FIG. 12 , a shape of the cut part12 may be changed by adjusting the first width W21 and the second widthW22. Specifically, when the size of the first width W21 is increased, asize of an upper part of the cut part 12 may be increased. And, when thesize of the second width W22 is increased, a size of a lower part of thecut part 12 may be increased. In FIG. 10 , FIG. 11 , and FIG. 12 , thesize of the first width W21 may be substantially the same as the size ofthe second width W22. In other words, difference between the size of thefirst width W21 and the size of the second width W22 may be equal orless than 1% of the size of the second width W22. And, the shape of thecut part 12 may be changed by adjusting the size of the third width W11of the modified part 11. Specifically, when the size of the third widthW11 of the modified part 11 is increased, a width W12 of a middle partof the cut part 12 may be increased.

FIG. 10 , FIG. 11 , and FIG. 12 may illustrate the shape of the cut part12 when a set of the first width W21, the second width W22, and thethird width W11 of the modified part 11 is adjusted differently. FIG. 10may illustrate the shape of the cut part 12 when the sizes of the firstwidth W21 and the second width W22 each are about 8 the size of thethird width W11 of the modified part 11 is about 14 and an etching timeis about 200 seconds. FIG. 11 may illustrate the shape of the cut part12 when the sizes of the first width W21 and the second width W22 eachare about 201 μm, the size of the third width W11 of the modified part11 is about 141 μm, and the etching time is about 200 seconds. FIG. 12may illustrate the shape of the cut part 12 when the sizes of the firstwidth W21 and the second width W22 each are about 61 μm, the size of thethird width W11 of the modified part 11 is about 61 μm, and the etchingtime is about 200 seconds. Depending on these parameters, the width W12of a middle part of the cut part 12 and the shape of the cut part 12 maybe changed as shown in FIGS. 10 to 12 .

FIG. 13 and FIG. 14 are cross-sectional views taken along line II-II′ ofFIG. 5 .

Referring to FIG. 13 and FIG. 14 , the shape of the cut part 12 may bechanged by the transmittance of the glass substrate 10 with respect tothe laser pulse 30. FIG. 13 and FIG. 14 illustrate the shape of the cutpart 12 when the transmittance of the glass substrate 10 is different.FIG. 13 illustrates that the transmittance of the glass substrate 10 isabout 25%, and FIG. 14 illustrates that the transmittance of the glasssubstrate 10 is about 50%.

When the transmittance of the glass substrate 10 is relatively low (forexample, the transmittance of the glass substrate 10 is about 25%), theglass substrate 10 absorbs relatively large amount of the laser pulse30, and the second etch protection layer 22 may be removed relativelyless. Accordingly, the size of the second width W22 may be smaller thanthe size of the first width W21, and the shape of the cut part 12 may beasymmetry between the upper part of the cut part 12 and the lower partof the cut part 12. In order that the cut part 12 does not have anasymmetric shape, the transmittance of the glass substrate 10 may beabout 50% or more.

FIG. 15 is a diagram for explaining a laser pulse according to anembodiment.

Referring to FIG. 15 , the glass manufacturing method may furtherinclude following steps: generating a laser pulse 30; and irradiatingthe glass substrate 10 with the laser pulse 30 through a laser scanningunit 3.

The laser scanning unit 3 may include a plurality of mirrors, and maychange a direction of a laser pulse 2 entering the laser scanning unit 3from a laser generator 1. In an embodiment, the laser scanning unit 3may further include an f-theta lens 4. The f-theta lens 4 may correct afocus of the laser pulse 30 when the laser pulse 30 is irradiated on theglass substrate 10.

FIG. 16 is a perspective view showing a glass substrate according to anembodiment.

Referring to FIG. 16 a glass substrate 100 having a rectangular shape ina plan view is illustrated, but a shape of the glass substrate 100according to the invention is not limited to the rectangular shape. Forexample, the shape of the glass substrate 100 may be a round shape. Theglass substrate 100 may include an upper surface 101, a lower surface102 opposite to the upper surface 101, and a side surface 103 connectingthe upper surface 101 and the lower surface 102. The side surface 103 ofthe glass substrate 100 may include a cut part 200. The cut part 200 mayinclude a first chamfered part 110 and a second chamfered part 120. Theglass substrate 100 may include a cut part 200. The cut part 200 may bea surface cut by the method described with reference to FIGS. 1 to 15 .

The glass substrate 100 may include soda-lime, alumo-boro-silicate,earth alkali alumo-silicate, or earth alkali alumo-boro-silicate.

FIG. 17 is a cross-sectional view of the glass substrate of FIG. 16taken along line extended in in a first direction DR1.

Referring to FIG. 17 , the first chamfered part 110 may be adjacent tothe upper surface 101. The second chamfered part 120 may be adjacent tothe lower surface 102.

The first chamfered part 110 may have a curved surface. Specifically,the first chamfered part 110 may have a first curvature radius R110. Thesecond chamfered part 120 may have a second curvature radius R120. Thefirst curvature radius R110 may be larger than the second curvatureradius R120.

FIG. 18 is a perspective view showing a glass substrate according toanother embodiment. A description overlapping with the glass substrateof FIG. 16 will be omitted.

Referring to FIG. 18 , the side surface 103 may include a cut part 200.The cut part 200 may include a first chamfered part 110, a secondchamfered part 120, and a flat part 130. The cut part 200 may be asurface cut by the method described with reference to FIGS. 1 to 15 .

FIG. 19 is a cross-sectional view of the glass substrate of FIG. 18taken along a line in the first direction DR1.

Referring to FIG. 19 , the first chamfered part 110 may be adjacent toan upper surface 101. The second chamfered part 120 may be adjacent to alower surface 102.

The first chamfered part 110 may have a curved surface. Specifically,the first chamfered part 110 may have a first curvature radius R110. Thesecond chamfered part 120 may have a curved surface. Specifically, thesecond chamfered part 120 may have a second curvature radius R120. Theflat part 130 may have a flat surface. The flat part 130 may be parallelto a plane defined by the second direction DR2 and a third directionDR3. (See FIG. 18 ) The flat part 130 may be disposed between the firstchamfered part 110 and the second chamfered part 120. In other words,the flat part 130 may connect the first chamfered part 110 and thesecond chamfered part 120. The first curvature radius R110 may be largerthan the second curvature radius R120.

Although certain embodiments and implementations have been describedherein, other embodiments and modifications will be apparent from thisdescription. Accordingly, the inventive concepts are not limited to suchembodiments, but rather to the broader scope of the appended claims andvarious obvious modifications and equivalent arrangements as would beapparent to a person of ordinary skill in the art.

What is claimed is:
 1. A glass comprising: an upper surface; a lowersurface opposite to the upper surface; and a side surface connecting theupper surface and the lower surface, wherein the side surface comprisesa cut part comprising: a first chamfered part which is concave, has afirst curvature radius, and is adjacent to the upper surface; and asecond chamfered part which is concave, has a second curvature radiusless than the first curvature radius, and is adjacent to the lowersurface.
 2. The glass of claim 1, wherein the cut part further comprisesa flat part connecting the first chamfered part and the second chamferedpart.